Iris biometrics is now considered one of the trilogy of the most important biometrics: face, fingerprint, and iris. The U.S. military is utilizing iris recognition to help prevent terrorism. Several nations around the world are in the process of creating National ID programs that will include all three of these biometrics. FIG. 1 is a schematic diagram illustrating an iris recognition system. As shown, a typical iris recognition system includes three key components: a light source, a camera unit, and a data processing unit. Natural light often reflects off the iris, creating glare that can obstruct part of the view of the iris. To avoid such glare, the light source generally uses infrared light as illumination, which is invisible to the human eye. The camera unit uses an infrared camera to take a clear and detailed image of the iris and sends the image to the data processing unit for processing and recognition.
Nowadays, iris recognition systems have been made as small standalone devices or incorporated into various consumer electronics, such as mobile phones, tablet computers, personal computers, laptop computers, or webcams. As such, the size of the system needs to be made smaller and smaller. As part of the solution, infrared light-emitting diodes (or IR LEDs) have been widely used for making the light sources. Such an IR LED based light source generally also includes a substrate for mounting the IR LED and a lens for focusing the light emitted by the IR LED.
IR LED based light sources for iris recognition systems are currently available on the market. But they are expensive and difficult to make. Their manufacturing process requires cutting a sheet of substrate into individual substrates, mounting a LED onto each substrate, bonding a supporting structure with each substrate, and bonding a lens with the supporting structure. The supporting structures and the lenses are separately molded and cut into individual pieces before bonding with each substrate. Such manufacturing process is complicated and difficult to scale for mass production.
U.S. Pat. No. 8,530,250 to Ichikawa et al. (“Ichikawa”) discloses a method for mass producing LED devices having resin packages. According to the disclosed method, a thermosetting resin is molded together with a lead frame to create a resin-molded body, LEDs are installed inside the concave portions of the resin-molded body and are sealed by a sealing member (e.g., epoxy resin, modified epoxy resin, silicone resin, modified silicone resin, acrylate resin and urethane resin of a thermosetting resin), and the resin-molded body are cut into individual LED devices. However, such LED devices do not have light focusing lenses and therefore cannot be used as light sources for iris recognition systems. Furthermore, the disclosed device's LED is already covered by a sealing member made from epoxy resin or similar polymer material, lenses made from such materials won't be effective in focusing light emitted from the LED.